Reading privacy policies takes 10 minutes on average

Too long to read: Researchers

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Website privacy policies take on average 10 minutes to read and sometimes run into thousands of words, researchers have found. While some are short, others would take over half an hour to read.

Researchers Aleecia McDonald and Lorrie Faith Cranor of Carnegie Mellon University looked at online privacy policies and how long it would take to read them. While one policy they looked at was just 144 words long, they found one policy on a popular site that ran to 7,669 words, around 15 pages of text.

The average length of privacy policies used by the 75 most popular US websites is 2,500 words, the research (pdf) found. Using the reading speed of 250 words per minute which is typical for those who have completed secondary education, the average policy would take 10 minutes to read.

The length of privacy policies is often cited as one reason they are so commonly ignored. "Studies show privacy policies are hard to read, read infrequently, and do not support rational decision making," said the researchers, acknowledging the fact that the policies are rarely read.

The researchers also investigated how quickly people could read privacy policies when they were just skimming it for pertinent details. They timed 93 people as they skimmed a 934-word privacy policy and answered multiple choice questions on its content.

Though some people took under a minute and others up to 42 minutes, the bulk of the subjects of the research took between three and six minutes to skim the policy, which itself was just over a third of the size of the average policy.

The researchers used their data to estimate how much it costs US citizens to read the privacy policy of every site they visit once a year if their time was charged for. Were people to actually read the policies and charge for that time it would cost $652bn a year.

Though that figure has limited usefulness, because people rarely read whole policies and cannot charge anyone for the time it takes to do this, the researchers concluded that readers who do conduct a cost-benefit analysis might decide not to read any policies.

"Preliminary work from a small pilot study in our laboratory revealed that some internet users believe their only serious risk online is they may lose up to $50 if their credit card information is stolen. For people who think that is their primary risk, our point estimates show the value of their time to read policies far exceeds this risk. Even for our lower-bound estimates of the value of time, it is not worth reading privacy policies though it may be worth skimming them," said the research.

"This leads to two implications. First, internet users likely do not understand the risks to their privacy … second, if the privacy community can find ways to reduce the time cost of reading policies, it may be easier to convince internet users to do so. For example, if we can help people move from needing to read policies word-for-word and only skim policies by providing useful headings, or if we can offer ways to hide all but relevant information and thus reduce the effective length of the policies, more people may be willing to read them," it said.

The researchers concluded that in order for web users' privacy to be protected, some regulation may be necessary.

"Some corporations take the view that their users should read privacy policies and if they fail to do so, it is evidence of lack of concern about privacy," they said. "Instead, we counter that websites need to do a better job of conveying their practices in useable ways, which includes reducing the time it takes to read policies. If corporations cannot do so, regulation may be necessary to provide basic privacy protections."

Struan Robertson, a technology lawyer with Pinsent Masons and editor of OUT-LAW.COM, said that in the UK organisations should layer their privacy policies.

"Certain information should be given without the need for any clicks," he said. "This is the data protection notice and its appearance should be a mandatory screen in any online process. The additional details can go into a privacy policy.

"Before a user submits any personal details at a site, this notice should identify the data controller (generally the company behind the website), the purposes for which they will use the details, and anything else needed to ensure fairness," said Robertson.

"This should be an unavoidable step, to comply with the Data Protection Act. However, we recommend that sites give additional information in a privacy policy, accessed by a link from this notice and through privacy policy links on each page of the site," he said.

"This layering of information is important to compliance and also usability. As long as information is presented in a way that lets users skim the essentials, it will not matter to the site's compliance if the user decides to read no further – though it's a sensible step to offer the additional information as reassurance to those who want it," he said.